1. Field of the Invention
The present invention relates to a method and a device for treating fine particles contained in El liquid.
2. Description of the Related Art
Conventionally, fine particles in a medium have been processed in various fine particle producing fields such as pigment producing and polymer fine particle producing. The fine particles are processed since mainly dissolution components and ion components (diffusible substance) of organic substances and inorganic substances of various chemicals used during manufacturing adsorb to the surface of the fine particles, and the fine particles are polluted.
In a general method for processing the fine particles, a slurry containing the fine particles which have been basically polluted is put in a large quantity medium (processing liquid) having no diffusible substance, or the slurry is showered with the processing liquid. Thereby the diffusible substances are diffused and diluted to reduce the concentration of the diffusible substances on the surface of the fine particles. The method is repeated as necessary, and a predetermined target is achieved.
The device is basically a batch process system using a paper filter or the like. That is, the paper filters are first selected according to the particle diameter of fine particles to be processed. The paper filter selected is set in an equipment such as a nutsche. While a collecting container of a filtrate is decompressed by a vacuum pump or the like, the liquid containing the fine particles to be processed is put on the paper filter. If the selection of the paper filter is correct, only the liquid which is almost filtered-off is collected from the nutsche or the like to the collecting container. After all fine particles in the medium are collected on the paper filter, the liquid (processing liquid) having no diffusible substance is poured on the fine particles on the paper filter, and the fine particles are processed. In fine particles having a large particle diameter or a system treated easily, a targeted processing state can be obtained. However when the fine particles have a more minute particle diameter or require substantial processing, the fine particles on the paper filter are collected and transferred to another container, and the fine particles are dispersed again in the liquid having no diffusible substance, Then the above described operation is repeated.
In order to improve the processing efficiency, the medium liquid is removed as much as possible from the fine particle aggregates after filtration, and the fine particle aggregates are processed in the liquid having no diffusible substance, or dispersed again in the medium having no diffusible substance. There are cases in which instead of using the paper filter, a filter cloth having a large region is used, and instead of performing filtration by the decompression method, a pressurizing method, or showering of the processing liquid is performed by a high-pressure atomization liquid, thereby improving the efficiency. However, in principle, the above described process is performed.
Meanwhile, in recent years, research has been carried out on various methods for performing chemical reaction and unit operation or the like in the micro field. In this connection, an extraction method and device, and a separation method and device have been proposed in view of the short diffusion time. Such devices and methods use a solvent extraction technique using a micro fluid system, but they have never been used for processing various fine particles (refer to, for example, Japanese Patent Application Publication (JP-A) No. 2002-361002).
As described above, in order to process fine particles efficiently according to the conventional process, it is necessary to remove the liquid as much as possible from the solid on the paper filter after filtration, and then to shower with the processing liquid or to disperse the solid again in the medium having no diffusible substance. However, the more the medium liquid is removed from the fine particle aggregates to improve the processing efficiency, the more rigid and stronger the fine particle aggregates become. Therefore, the liquid put in sequentially cannot permeate between the fine particles, and the surface of individual fine particles cannot be processed sufficiently.
In addition, when the fine particle aggregates are dispersed again in the processing liquid, since the aggregation strength of the fine particle aggregates is strong, the aggregates do not loosen sufficiently, and the surface of each of the individual fine particles cannot be processed. Thus, a problem arises in which the processing efficiency conflicts with the operation efficiency. Furthermore, in order to improve the processing ability, it is necessary to repeat a similar operation, which leads to a problem of loss of the fine particles to be obtained during processing of the container and collection of the solid.